The whole saga around the rejection of the official Google Voice client for the iPhone continues to play a prominent role on many websites. We all remember that the FCC had asked the three companies involved, AT&T, Google, and Apple, to answer a number of questions, but Google had censored a part of its letter. The censored section has now been published by Google.

AT&T originally deployed HSDPA 3.6 in the 1900MHz PCS band. They are now rebanding their HSDPA service to the 850MHz "Cellular" band to get better in-building penetration and capacity mainly due to their large number of iPhone users.

They never had any 2100MHz spectrum. In the US 2100MHz is used for sat<->ground and other microwave stuff. The FCC had allocated 2100Mhz long before Europe chose 2100MHz for their UMTS 3G service.

The rebanding to 850MHz means that suddenly many of the AT&T 2G users lose coverage, because 1900MHz just doesn't go as far and that's where the 2G coverage now in markets like San Francisco and New York. AT&T basically screwed over the 2G users to help out the iPhone 3G[S].